Please use this identifier to cite or link to this item: http://lib.jncasr.ac.in:8080/jspui/handle/10572/2348
Title: Thermal Expansion, Anharmonicity and Temperature-Dependent Raman Spectra of Single- and Few-Layer MoSe2 and WSe2
Authors: Late, Dattatray J.
Shirodkar, Sharmila N.
Waghmare, Umesh V.
Dravid, Vinayak P.
Rao, C. N. R.
Keywords: Physical Chemistry
Atomic, Molecular & Chemical Physics
Field-Effect Transistors
Electric-Field
Solar-Cells
Graphene
Ws2
Films
Gas
Semiconductor
Electronics
Crystals
Issue Date: 2014
Publisher: Wiley-V C H Verlag Gmbh
Citation: Late, DJ; Shirodkar, SN; Waghmare, UV; Dravid, VP; Rao, CNR, Thermal Expansion, Anharmonicity and Temperature-Dependent Raman Spectra of Single- and Few-Layer MoSe2 and WSe2. Chemphyschem 2014, 15 (8) 1592-1598, http://dx.doi.org/10.1002/cphc.201400020
Chemphyschem
15
8
Abstract: We report the temperature-dependent Raman spectra of single-and few-layer MoSe2 and WSe2 in the range 77-700 K. We observed linear variation in the peak positions and widths of the bands arising from contributions of anharmonicity and thermal expansion. After characterization using atomic force microscopy and high-resolution transmission electron microscopy, the temperature coefficients of the Raman modes were determined. Interestingly, the temperature coefficient of the A(2u)(2) mode is larger than that of the A(1g) mode, the latter being much smaller than the corresponding temperature coefficients of the same mode in single-layer MoS2 and of the G band of graphene. The temperature coefficients of the two modes in single-layer MoSe2 are larger than those of the same modes in single-layer WSe2. We have estimated thermal expansion coefficients and temperature dependence of the vibrational frequencies of MoS2 and MoSe2 within a quasi-harmonic approximation, with inputs from first-principles calculations based on density functional theory. We show that the contrasting temperature dependence of the Raman-active mode A(1g) in MoS2 and MoSe2 arises essentially from the difference in their strainphonon coupling.
Description: Restricted Access
URI: http://hdl.handle.net/10572/2348
ISSN: 1439-4235
Appears in Collections:Research Articles (Umesh V. Waghmare)
Research Papers (Prof. C.N.R. Rao)

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